Temperature indicating device for internal combustion and explosion engines



March 12, 1935. M. A. RENARD TEMPERATURE INDICATING DEVICE FOR INTERNAL COMBUSTION AND EXPLOSION ENGINES Filed Aug. 22, 1932 1 .wg 1 F R a YEL Tog MM/Z Patented Mar. 12, 1935 UNITED STATES TEMPERATURE INDICATING DEVICE FOR INTERNAL COIVIBUSTION AND EXPLOSION ENGHWES Melanie Arsne Renard, Antheor, via Agay, France Application August 22, 1932, Serial No. 629,978

In France December 7, 1931 8 Claims.

The power-producing apparatus in the various industrial power plants, are always provided with devices for the control of their operation; these controlling devices being voltmeters and ammeters in the case of electric motors, pressuregauges in the case of boilers, pressure and vacuum indicators in the case of steam engines, and the like. In contradistinction thereto the internalcombustion and explosion engines are not yet provided with similar means by which their operation may be controlled.

It has been proposed to employ pressure-gauges for this purpose, but after various attempts, they were abandoned because of their rapid deterioration and of the clogging of the pipes.

The present invention relates to an apparatus for the control of the operation of the cylinders of internal-combustion and explosion engines, and is chiefly characterized by the fact that it comprises a combination with a thermometric device which is mounted on the cylinder or cylinder-head in such manner that it will be subjected to the variations of the temperature said variations being proportional to the variations of the temperature in the cylinder, of an indicating device operated by the aforesaid device, directly or indirectly, according to the variations 0! temperature to which this device is subjected.

In this manner, the apparatus will show at all n times the variations of temperature occurring at a given point of the cylinder, and hence the variations of pressure in this cylinder, which as is well known will depend upon such temperature variations.

The first-mentioned thermometric device must obviously be located at a point where the temperature will be compatible with the operating conditions of said device.

Thus with the use of an ordinary mercury thermometer which, in practice, will not indicate more than 350 0., this point will be selected and arranged in such manner that its temperature should not exceed 350 C., when the engine is in full operation and the power unit is heated to the maximum. The same conditions will apply to thermometers operating by vapour tension, by the expansion of mercury, or the like, whose measuring capacity may attain 600 to 700 C. in practice.

According to another feature of the invention, the thermometric device is combined with the sparking-plug.

In the case of an engine having several cylinders, each cylinder will obviously be provided with a controlling apparatus in conformity to the invention, and the juxtaposition of the indicating devices, for instance upon the dash-board of the vehicle, will provide for a comparative control of the operation of the different cylinders, thus showing the operation of the whole engine.

In the accompanying drawing, which is given solely by way of example:

Fig. 1 is a lengthwise section showing the combination of a sparking-plug in conformity to the invention, comprising, in combination, a sparking-plug and a thermometer containing a liquid such as mercury or the like.

Fig. 2 is a like section of an apparatus in which the thermometer is of the vapour-tension type.

Fig. 3 shows a section of another apparatus comprising a thermometer adapted for distance reading.

Fig. 4 is a diagrammatic view showing an engine for motor vehicles, having several cylinders, each cylinder being provided with a device in conformity to the invention.

In the form of construction shown in Fig. 1, the sparking plug, which may be of any suitable type, comprises in the known manner a metallic body 1 which is adapted to be screwed in the cylinderhead or in the cylinder of an engine, and a central metallic electrode 2, separated from the said body by an insulating bushing 3. The central electrode 2 has a longitudinal bore 4, adapted for the insertion of a thermometer 5 which may contain mercury or any other suitable liquid. The bulb 6 of the thermometer is situated in the central insulating bushing 3 in such a way that the temperature to be measured in the point where said bulb is placed will not exceed 350 0., approximately, the heat from the explosion chamber of the engine being imparted to the thermometer by conduction alongthe rod of the electrode 2.

In the construction shown in Fig. 2, a vapourtension thermometer 5 is provided with an indicating dial? and serves itself as a central electrode by means of its rod 2. It is situated within the insulation 3. The said thermometer indicates higher temperatures than thepreceding one because of the place occupied by its operative part 6 which approaches more the engine cylinder.

Fig. 3 indicates a thermometer 5 provided with means for reading at a certain distance. Said thermometer operates by the expansion of meroury, and is mounted in a special lateral chamber 8 forming part of the body 1 of the sparking plug. The bulb 6 of this thermometer is in a more direct contact with the gas, and the thermometer will thus indicate temperatures up to 600 C.

which are concerned in the explosions.

For the distance reading, a so-called maximum and minimum thermometer may also be employed, said thermometer cooperating for instance with a suitable electric circuit by means of a pair of contacts.

The operation of the aforesaid apparatus is as follows Considering for example a four-cylinder engine 9 in which each cylinder is provided (Fig. 4) with a combined sparking plug and thermometer of the construction shown, in Fig. 1, it will be observed that when the engine is started,

the mercury rises more or less in the four thermometers 5 according to the greater or less amount of heat which is produced by the explosions in the corresponding cylinders. This produced amount of heat depends for a given power, upon the state of the different members In this way, if a sparking-plug is not working properly, if a valve or piston is leaking, or if the packing is defective, this will provocate in any case a reduction of the temperature in the corresponding cylinder, and thus a decrease of the number of degrees indicated by the corresponding thermometer, which is to be considered comparatively with the other thermometers.

It will thus be an easy matter for the driver of a motor vehicle to locate the causes of the defective-operation of the engine. With the use of the distance-reading temperature indicators of the type shown in Fig. 3, whose dials may be mounted at on the dash-boards 11 of the vehicle, the

observations can be still more readily made, and while on the road the driver is enabled at 'any time to make useful comparisons between the cylinders, and even to control-and determine the working conditions of the engine with reference to a given speed of the vehicle.

Obviously, the said invention is not limited to the forms of construction herein described and represented; which are given solely by way of example.-

The sparking-plugs, the thermometer devices, or their combinations, may have all possible forms and arrangements. Use may be made of all metals, alloys or insulation which by their greater or less aptitude .for conduction or radiation are found necessary for the proper working of the apparatus.

As above mentioned, the invention relates, to all controlling apparatus which are based upon the thermometric principle, even when these are not employed in conjunction with the ignition plug. The thermometric device may preferably be mounted in or upon simple plugs which are screwed at suitable points of the cylinders or the cylinder-heads. It is evident that the invention is applicable to internal combustion enginesas well as to explosion engines.

Having now describgd my invention, what I claim as new and desire to secure by Letters Patent is:

p 1 In a cylinder or an internal combustion or like engine, a spark plug provided on the cylinder, a vapour tension thermometer disposed inside the housing of the spark plug and a distant indicator associated with said thermometer.

2. In a cylinder of an internal combustion or like engine a spark plug provided on the cylinder, a fixed electrode in said spark plug, a longitudinal hole provided in the upper portion of said electrade and a thermometer, the sensitive part of which is located in said hole.

3. In a cylinder of an internal combustion or like engine, a spark plug provided on the cylinder, a fixed electrode in said spark plug, a longitudinal hole provided in the upper portion of said electrode and a mercury thermometer, the sensitive part of which is located in said hole.

' 4. In a spark plug a fixed electrode, a longitudinal hole provided in the upper portion of said electrode and a thermometer, the sensitive part of which is located in said hole.

5. In combination with a spark plug, a thermometer of the vapour tension type, situated in the central electrode of said spark plug.

6. In a cylinder of an internal combustion or like engine, a spark plug, a central electrode in said spark plug and a fluid thermometer centrally located in said spark plug, the sensitive part of said thermometer filled with the heat responsive fluid being formed in the upper'portion of said electrode.

'7. In a spark plug, a central electrode in said spark plug and a fluid thermometer centrally located in said spark plug, the sensitive part of said thermometer filled with the heat responsive fluid being formed in the upper portion of said electrode.

8. In a cylinder, a controlling device according to claim 6 in which the thermometer is of the vapor tension type.

MELANIE ARSENE RENARD. 

